I am not able to download any app after changing my country/reguio

Unfortunately you have provided too little information for us to propose a specific solution. Describing what happens when you try, and the exact wording of any error messages, would greatly aid us in helping you. In the meantime review these documents if you think they apply:

Did you try restarting your device?

Click on this link "If you can’t download or update apps on your iPhone or iPad " --> If you can’t download or update apps on your iPhone or iPad - Apple Support

If the first 5 don't help, use the 6th.

Considerations:

Do you have the same problem when using a different Wi-Fi network?

Does restarting your device make any change?

Can you download apps normally on another device?

If a feature on your device is not working, it may have been disabled. See how to 'Use Screen Time on an iPhone, iPad, or iPod touch' by clicking here --> Use Screen Time on your iPhone, iPad, or iPod touch - Apple Support Go to: Content & Privacy Restrictions > iTunes & App Store Purchases

If instead you see a message that says "Your account has been disabled in the App Store and iTunes" click on this --> If a message says 'Your account has been disabled in the App Store and iTunes' - Apple Support

Resolve issues between iTunes and third-party security software - Resolve issues between iCloud for Windows or iTunes and third-party security software - Apple Support - You can’t connect to iTunes Store to buy or download content.

If you see 'app needs to be updated' after updating to iOS 14.5, click here --> If you see 'app needs to be updated' after updating to iOS 14.5 - Apple Support

Have you entered a payment method? This document explains how to 'Change, add, [review,] or remove Apple ID payment methods' on an Apple mobile device, a Mac, or a PC; click here --> Add a payment method to your Apple ID - Apple Support

Apple Recommended article by ASC contributor Urquhart1244 --> This Apple ID has not yet been used with … - Apple Community with various suggestions about network, payment and log-in issues.

Check Apple's system status --> Apple - Support - System Status

If you can't connect or sign in to iCloud --> If you can't connect or sign in to iCloud - Apple Support

"If you can't connect to the App Store, iTunes Store, or Apple Books" click here --> If you can't connect to the App Store, iTunes Store, or other Apple services - Apple Support

- If none of the suggestions work, try the last one: "If you’ve tried all of the above steps and you still can’t connect, contact Apple Support."

Click here --> https://support.apple.com/choose-country-region Select your country, then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service --> "See a list of Apple phone numbers around the world."

Click here --> https://support.apple.com/HT201232

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Click here --> https://support.apple.com/HT207165

If the first 5 don't help, use the 6th.